Commutator termination



Feb. 18, 1969 J. R. KELLER COMMUTATOR TERMINATION Filed Oct. 15, 1965United States Patent 3,428,843 COMMUTATOR TERMINATION Joseph RichardKeller, Harrisburg, Pa., assignor to AMP I Incorporated, Harrisburg, Pa.Filed Oct. 13, 1965, Ser. No. 495,417 US. Cl. 310-234 Int. Cl. H01r39/32 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to theart of commutators and more particularly to a new and improved means forconnecting commutator leads to the metallic segments of a commutator.

At the present time there are numerous methods for connecting the leadsfrom an armature winding to a commutator. The usual method is to effectthe connection by soldering the lead to the commutator. This method hasthe disadvantages that the leads must be stripped prior to soldering andaluminum leads cannot normally be used. Also, there is extreme heatgenerated during the rotation of the armature and commutator with theresult that the solder often melts and the leads will become disengagedfrom the commutator due to the centrifugal force set up by the rotation.

To avoid this problem it has been suggested to effect the connectionwithout solder by mechanically deforming a portion of the metallicsegments of the commutator whereby these portions will surround theleads to provide a mechanical and electrical connection. Examples ofthis method are found in US. Patents Nos. 2,476,795 and 2,572,956.Although this method is an improvement over the soldering method thereare still serious drawbacks. One drawback is that it is expensive andtime consuming to machine the metallic segments to provide the necessaryslots for receiving the leads. Also, there is no real assurance thatthere will be an electrical connection if the leads are not stripped,this being the result of attempting to deform a large mass of metalaround a comparatively small lead.

It is therefore an object of the present invention to provide aconnection which avoids the above drawbacks.

Another object is to provide a commutator which is simple andinexpensive to produce.

A further object is to provide an improved means and method forconnecting the leads to a commutator by simple crimping tools.

Other objects and attainments of the present invention will becomeapparent to those skilled in the art upon a reading of the followingdetailed description when taken in conjunction with the drawings inwhich there is shown and described an illustrative embodiment of theinvention; it is to be understood, however, that this embodiment is notintended to be exhaustive nor limiting of the invention but is given forpurpose of illustration in order that others skilled in the art mayfully understand the invention and the principles thereof and the mannerof applying it in practical use so that they may modify it in variousforms, each as may be best suited to the conditions of a particular use.

In the drawings, in which like reference numerals refer to like parts:

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FIGURE 1 is a fragmentary perspective view of the commutator assembly;

FIGURE 2 is a front elevational view of the commutator in position to becrimped; and

FIGURE 3 is a side elevational view of the commutator of FIGURE 1.

The commutator of the present invention is shown generally at 10 andcomprises an annular portion 12 in the form of a cylinder having acentral opening 14 for reception of the shaft of an armature. A hub-likeportion 16 is formed integrally with portion -12 and has a plurality ofradial arms 18 extending therefrom, each said arm terminating at itsdistal end in a concave surface 20. A plurality of openings 22 areuniformly arranged in hub 16 with the openings 22 bearing apredetermined relationship to the arms 18. The parts above described aremade of a dielectric material such as phenol or mica so that they arenonconductive.

A plurality of metallic commutator segments are indicated generally at24, only one being shown in FIG- URE 1 for ease of illustration, andcomprise a base portion 26 having a raised lance 28 therein and aplurality of legs 30 which may be bent downwardly and at an angle so asto provide a firm mechanical connection with the annular portion 12. Thesegments 24 further comprise a barrel portion 32 of open U-shapedconfiguration, the barrel having a plurality of serrations 34 on theinside surface thereof.

The segments 24 may be secured to cylinder 12 by any suitable means butit is found desirable to mold them into place. This is accomplished byproviding the seg ments in strip form and placing the strip in asuitable mold and thereafter injecting the dielectric material into themold to form the cylinder 12, hub 16, and arms 18 and at the same timethe segments 24 will be retained by the dielectric material flowingaround the legs 30. The portions of the strip connecting the individualsegments would then be removed so that the segments are not inelectrical communication with each other.

A commutator lead 36 is shown and extends from an armature winding. Thelead is passed through barrel 32, wrapped around lance 28, and passedagain through barrel 32 whereby the lead is in a position to be securedto the commutator. A pair of crimping dies 38 and 40 are shown and aredisposed apart. Suitable means, not shown, may be provided on thecrimping apparatus for insertion into the openings 22 to therebyposition the commutator relative to the crimping apparatus. Theconnection is effected by advancing die 38 into contact with barrel 32whereby the latter will be bent over into gripping engagement with thelead 36. Also, the serrations 34 will penetrate the insulation on lead36 to insure electrical communication between the lead and the segment24. The radial arms 18 serve as the back up or anvil for the crimpingoperation with the concave surface 20 aiding in the forming of thebarrel. By using a dielectric anvil there is a considerable savings incost as compared to using a larger metallic segment, which segment isnormally copper. The force exerted during the crimping operation may bequite large and it is therefore desirable, although not essential, thatthe two dies 38 and '40 be operated simultaneously so that the forceswill be opposed and will tend to cancel.

It is to be noted that the crimping force may be sufficient on occasionto crack the arms 18. However, this would not be harmful to thecommutator because once the barrel overlying a particular arm iscrimped, the arm no longer has any utility so its cracking or breakingis of no consequence.

It can thus be seen that the objects of the invention have been achievedand a simple and inexpensive commutator has been produced which can bequickly and easily connected to the leads of an armature Winding.

Changes in construction will occur to those skilled in the art andvarious apparently different modifications and embodiments may be madewithout departing from the scope of the invention. The matter set forthin the foregoing description and accompanying drawings is offered by wayof illustration only. The actual scope of the invention is intended tobe defined in the following claims when viewed in their properperspective against the prior art.

What is claimed is:

1. In a commutator, a non-metallic member comprising a first generallycylindrical portion having a central opening for receiving an armatureshaft, and a second portion integral with said first portion andcomprising a hub having a plurality of radial arms extending therefrom.

2. The member of claim 1 wherein said arms are equi-distantly arrangedabout said hub and wherein said arms terminate in a concave surfacealong their outer ends.

3. The member of claim 2 further comprising a series of openingsdisposed in said hub portion, there being one such opening for each ofsaid radial arms.

4. A commutator element comprising a first nonmetallic member, saidmember having an annular portion and a hub-like portion, a plurality ofraidal arms extending from said hub-like portion, a series of metallicsegments disposed about the periphery of said non-metallic member andsecured thereto, said segments being aligned with said radial arms, eachsaid segment comprising a commutator lead receiving portion overlyingone of said radial arms.

5. A commutator comprising an electrical insulating member, said memberhaving an annular portion and a hub portion, a plurality of radial armsextending from said hub portion, each said arm having an outer concavesurface adjacent the outer surface of said annular portion, and aplurality of metallic segments disposed around the periphery of saidinsulating member in alignment with said radial arms, each said segmentbeing out of contact with the segments adjacent thereto, said segmentshaving a first portion secured to the annular portion of the insulatingmember and having a second portion overlying the concave surface of saidradial arms, said segment second portion comprising a barrel having aplurality of serrations on the internal surface thereof, a lance formedin said segment first portion whereby a commutator lead, which passesthrough said barrel, around said lance, and back through said barrel, isconnected to said commutator by closing said barrel around said leadwith the barrel serrations piercing the insulation on said leads andcontacting the conductive wires of said leads, said radial arms actingas back up means for the closing operation on said barrels.

6. For use in a commutator assembly of an armature, an integral memberof insulating material comprising a generally cylindrical portion havinga central opening to receive an armature shaft, said portion havingcommutator segment stations on its outer surface, and a hub coaxial withsaid portion and having anvil elements associated with said stations andarranged to support crimpable extensions of said segments.

References Cited UNITED STATES PATENTS 1,881,341 10/ 1932 Apple 3'10235X 2,476,795 7/ 1949 Avigdor 310-23-3 3,080,615 3/ 1963 Carlson 29-597 XFOREIGN PATENTS 942,026 11/ 1963 Great Britain.

J D MILLER, Primary Examiner.

G. NUNEZ, Assistant Examiner.

US. Cl. X.R.

